1. Field of the Invention
The present invention pertains to devices and methods for producing denture parts, more particularly, using surface mapping and generation devices as well as to methods for surface mapping and surface generation for mapping and/or generating surfaces of teeth.
2. Prior Art
Fundamental technologies that can be used together with the present invention, or with which it can be combined, are disclosed in laid-open patents DE 44 39 307 A1 and
DE 197 21 688 A1 as well as WO 02/39056 A1, which can be cited, on the one hand, as the closest prior art for surface mapping and generation and methods for surface mapping and generation and, on the other hand, are herewith incorporated in full by reference into the present documents, since the present invention can be used and combined in all its configurations with this technology and, in that sense, advantageously refines and/or improves it, wherein also lie objectives of the present invention in some of its aspects.
WO 02/39056 A1 discloses a large amount of useful and/or essential information that is useful or at least advantageous for the comprehension and design of the present invention, so that WO 02/39056 A1 is extensively cited below.
In the original version of WO 02/39056 A1, its technical teaching achieves the objective of creating a surface mapping and generation device with devices for optimizing the process and/or cost.
According to WO 02/39056 A1, it is preferably provided that the devices for optimizing the process and/or cost contain raw material recovery devices, and/or that the devices for optimizing the process and/or cost contain an automatic controlling of the intensity of a laser light that is employed. Alternatively or additionally, it is preferable for the devices for optimizing the process and/or cost to be laid out such that two half-frames that show different positions or views are evaluated, with a pulsed laser being contained in particular for exposure.
Further alternative or additional configurations of a surface mapping device according to WO 02/39056 A1, more particularly for obtaining surface data of teeth, consist in the fact that the devices for optimizing the process and/or cost contain devices for carrying out a calibration procedure by evaluating superimposition errors at matching points, and/or that an image-recording device, more particularly, a CCD chip is arranged such that lines lie perpendicular to the displacement direction of the measuring table, taking into account the Scheimpflug angle.
An additional variant of a surface mapping device especially for obtaining surface data of teeth according to WO 02/39056 A1 is that the devices for optimizing the process and/or cost contain, in particular, devices for archiving three-dimensional jaw data and/or for simulating the bite position of the upper and lower jaws.
Special, preferably mechanical configurations of the surface mapping device are oriented according to the disclosures of FIGS. 3 and 4 and/or 5, 6 and 7 as well as the related description.
It is additionally preferred if, in the surface mapping and generation device especially for producing dentures, the devices for optimizing the process and/or cost contain devices for the optimized preparation of at least one tooth stump for the production and for the placement of a dental prosthesis thereon and/or devices for taking into account the bite position of the upper and lower jaws.
The surface mapping and/or generation methods according to WO 02/39056 A1 are characterized in that they contain one or more of the above-explained devices or function analogously thereto.
Finally, a patient data archival system that is characterized by a chip card and/or decentralized data storage units especially for tooth data is created by WO 02/39056 A1.
Individual aspects of WO 02/39056 A1 will be explained in even more detail below.
According to one aspect of WO 02/39056 A1, starting from surface mapping technologies, devices and methods as specified in the above-indicated publications, herein incorporated by reference, and subsequently referred to for simplicity as “scanners” or “scanning,” a raw material recovery means is provided in combination with, for instance, a milling machine. Together with the milling machine and an appropriate data processing system, the scanner constitutes a CAD-CAM system specifically for the production of gold or platinum dentures. The raw material recovery can preferably be implemented by equipping the milling machine, for instance, with, as one example, means for the suction of gold or platinum dust/chips. Considering the high costs for the raw materials gold or platinum, a considerable reduction of the costs for producing gold or platinum dentures is thereby advantageously achieved.
According to another aspect of WO 02/39056 A1, the scanner technology disclosed in the above-mentioned publications is further improved.
First, this is achieved according to WO 02/39056 A1 by an automatic regulation of the intensity of the laser light that is employed. Therein, the reflectivity of the [word omitted] to be mapped is detected via, for instance, the intensity of the light received by a CCD chip. The intensity of the laser light is then re-regulated based on the detection result. The improvement in this configuration is that measurement errors due to undershooting or overshooting of the measurement signal are thereby reduced. WO 02/39056 A1 pertains both to devices and to methods in keeping with the above explanation.
Second, the scanner technology within the scope of WO 02/39056 A1 is improved by an increase in speed in that, instead of a full frame from the camera/CCD chip consisting of two combined half-frames, two such half-frames that show different views are analyzed. The different views result from different relative positions of the tooth surface to be mapped and the device for recording this surface (e.g., a lone CCD chip or a camera therewith).
Particularly the above improvement, and also the scanning technology in general, can be advantageously refined by driving the laser being used in a pulsed mode similar to a stroboscopic effect and, for example, by displacing the table bearing the object whose surface is to be mapped, such as a tooth or a model thereof, particularly if this is done continuously. By virtue of the pulsed laser beam, instantaneous images or “still images” are prepared for each relative position of object and camera, since the object appears to be stationary during the brief time of exposure with one laser pulse and can be recorded by the camera in this position. It is particularly preferable for each individual laser pulse to be coupled to the recording of one half-frame.
Yet an additional improvement of scanner technology according to WO 02/39056 A1 lies in a calibration procedure, which corrects various spatial distortions of the ascertained measurement parameters. A body is measured in this case from several different views. The measurements are put together by way of matching algorithms. The superimposition errors occurring at various points of the object in this process are analyzed with regard to recognizing deviations in all directions. These deviations yield calibration errors, from which in turn calibration parameters in all directions and rotations of space are calculated. These calibration parameters can then automatically be taken into account by the data-processing system in additional measurements, whereby an enhanced measurement precision is advantageously achieved. Additional details in this regard can be deduced from the embodiment illustrated in FIG. 1.
Moreover, the scanner according to the even older prior art is improved by WO 02/39056 A1 in that a CCD chip (or in general a surface image mapping device) is arranged such that, for example, taking into account the Scheimpflug angle, the camera lines are perpendicular to, for example, the displacement direction of the measuring table on which the object to be mapped is installed. Additional details in this regard are illustrated in the embodiment according to FIG. 2. Thereby, a better utilization of the measuring field for surveying, teeth for example, is achieved; it must be noted that ordinary commercial chips are not square.
The known scanner technology can also be improved further by positioning and arranging the displacement and pivot axes of the object carrier, the object and/or the camera according to WO 02/39056 A1 such that a view into all the undercuts occurring in the jaw is possible if the teaching of WO 02/39056 A1 is utilized in, for instance, the field of dental surface mapping. This has the advantage that a completely automatic surveying/measuring strategy can be utilized.
According to another aspect of WO 02/29056 A1, diverse data-processing modules are advantageously used in different fields of dentistry.
Thus, WO 02/39056 A1 creates a scanner technology that is equipped with a data-processing system, preferably in the form of a standard computer with special software as the control unit, that is suitable for archiving, for instance, three-dimensional jaw data, more particularly, surface data. The archiving serves to replace previous archiving of such data in the form of plaster casts. In many fields of dentistry, it was previously necessary to preserve plaster casts of patients for up to 10 years, which resulted in an enormous demand for space. The electronic archiving of these data not only provides a remedy with regard to space needs; it also enables a faster, simpler and more economical utilization of the archived data. This it is possible, for instance, to acquire and archive 3D measurement data from previously healthy tooth surfaces. If, for instance, a tooth is to be replaced years later, this allows a reconstruction of the tooth in the form of a denture that can be produced, for example, on the basis of the archived data by generating its surfaces with milling technology.
Electronic archiving of jaw/bite data can also be advantageously used in many other respects, however. Thus, these data enable, by means of a suitable data-processing system, a simulation of the bite position of the upper and lower jaw. More particularly, this can be generated by first surveying the lower jaw, then placing a bite record (impression in the patient's mouth while biting) on top of the lower jaw and surveying it again. Thus both surfaces are acquired in the biting situation. The two data records can be displayed separately or together and all the associated dental analyses can be carried out, e.g., qualitatively or quantitatively (in the form of distance or volume measurements). As a complement, the complete upper jaw can be surveyed and spatially referenced by means of the bite record and, for instance, a matching software. Mastication motions can likewise be simulated on the computer by recording the jaw movement and the bite record. The referencing of the measurement data from the upper and lower jaws can also be employed for the modulation of a denture in connection with CAD-CAM technology.
An additional variant of WO 02/39056 A1 consists in a scanner technology with a data-processing system in the form, for instance, of a standard computer with suitable software as the control unit, so as also to be able to simulate the bite position of the upper and lower jaws with a particular orientation for an orthopedic treatment of the jaw. A treatment plan for a brace, for instance, can be simulated by subdividing in the software the dentition in tooth groups all the way down to individual teeth, to cite one possible example. Such groups of teeth or individual teeth can be moved and the final positions simulated. This permits answers to questions of whether the required space is available on the jaw ridge and what the bite will look like after therapy. Monitoring of therapy is possible with additional data-processing/software units, which can be combined modularly. A jaw can be repeatedly scanned at time intervals. The temporally successive images can then be played back as an interpolated “film.” This allows a comparison of the course of the actual treatment with the planned treatment and the formulation/performance of corrective measures. Such image series can, moreover, be archived and can make it easier, for instance, to provide evidence in lawsuits. Communication with expert committees and insurance companies is also facilitated.
Another aspect of WO 02/39056 A1 is a scanner technology that is equipped with a data-processing/electronic controller (by software, for instance) in order, for example, to simulate the bite position of the upper and lower jaws with particular orientation for oral-surgical therapy. Within the scope of this aspect of WO 02/39056 A1, in particular, the incorporation of measurement data of the jawbone (acquired, e.g., by computer tomography) is provided, by means of suitable software. The planning of therapy (an operation on the jaw, for example) is simulated by subdividing the dentition, the jaw and the jawbone into tooth/jaw section groups (all the way down to individual teeth) in, for example, software. The tooth groups/individual teeth can be moved and the final positions simulated. This enables the answering of questions as to whether the required space is available and what the patient will look like after the therapy. An additional data-processing/software module can be utilized in this case for monitoring the therapy. After segments of time have elapsed, the current status each time can be scanned. The images over time can then be played back as an interpolated “film.” The course of the actual treatment can be compared with the planned treatment and any necessary corrective measures can be derived therefrom. In an advantageous manner, this aspect of WO 02/39056 A1 enables the planning and simulation of implants. Archived image series to facilitate the provision of evidence in possible lawsuits and simpler, faster communication with expert committees and insurance companies are additional advantages.
Finally, a patient-data carrier such as a chip card that contains all person-related health and illness data also lies within the scope of WO 02/39056 A1. Such an individual data carrier can be integrated into a management and archiving system that, in particular, contains decentralized storage units for archiving large amounts of data which can be accessed by means of access devices on the data carrier. Thus, for instance, even master dental patient data, which can contain 3D jaw and individual tooth data of tooth surfaces and internal structures of individual teeth as well as generation data of dentures in use (material and milling data for example), can be archived and made easily available. Additionally, health insurance data, digital X-ray images, previous and current attending physicians and generally the entire medical history of a patient are stored. Special reading and analysis devices can also be provided within the technical teaching of WO 02/39056 A1 and, in certain circumstances, be integrated into the system. Advantages achieved here are, for instance, double archiving for the patient, better trace-back possibilities for health insurance agencies and data availability even in case of change of address.
The object of WO 02/39056 A1 is also an additional variant/configuration for the implementation of a pulsed measurement, as already presented in principle above.
A corresponding surface mapping unit or device consists, for example, of a linear table, a CCD camera, a frame grabber card and a laser line module. To acquire data, the laser line is permanently projected onto the object being measured. The measuring table is moved step-by-step underneath the measurement arrangement (laser line and CCD chip). After each step, there is a measurement.
The exact previous process in this regard is as follows. The measuring table moves into a start position and stops. The object must be stationary so that no “wobbling” of the image causes measuring inaccuracies. Then the CCD camera reads out a line (full-frame) and transfers the signal to the frame grabber card. Subsequently, the table is accelerated (starting ramp). Then the table is again braked and stopped in a specified position (braking ramp). The CCD camera then reads out the next line. This entire process runs in a darkened room. The laser diode can be regulated up only to a certain power if the signal is not to overshoot.
According to WO 02/39056 A1, it was an innovation at that time for the laser line to be projected stroboscopically onto the measured object, that is for light flashes to be regularly cast in the form of a laser line onto the object. The measuring table moves the object continuously beneath the measuring arrangement (laser line, CCD chip). A measurement takes place simultaneously with each light flash. In particular, the measuring table travels at a controlled/monitored speed that is matched to the flash controller. A flash is emitted at preferably regular intervals (time or travel distance of the table) and simultaneously a half-frame is read out from the CCD chip. This signal is transferred to the frame grabber card and analyzed by means of special software. The flash time is sufficiently short that “wobbling” that could result from the continuous table movement is negligible.
With the configuration from WO 02/39056 A1, the measuring process is accelerated by a factor of 5, since the startup and braking times of the table are eliminated and the light flashes are clocked sufficiently fast that half-frames can be read out. Another advantage resulting is that the controller can be designed more economically, since only a uniform feed rate need be guaranteed and it is not necessary to set a precise resting position. It is also advantageous that earlier optomechanical arrangements can continue to be used/employed, since the present innovation can be implemented or already exists in regard to controlling, regulation and software for the components. It is additionally advantageous that the flash used is considerably more intense than the laser signal previously used, whereby the measurement can be taken even in daylight and the measuring room need not be darkened, which considerably reduces the work and its cost and time requirements, particularly when measurement objects are changed.
Alongside the technical specifications on the subject of “stroboscopic laser” already specified above and just preceding, the scope of WO 02/39056 A1 also includes mechanical embodiments which, in their concept and concrete configurations as well as their operating methods, are considered worthy of protection and protectable, in combination and also on their own.
Particularly in comparison to the technical status of the device for producing a denture according to EP 98115809.0, WO 02/39056 A1 contains a number of concepts and configurations that render a corresponding device drastically more economical to produce and more secure in operation. These aspects of WO 02/39056 A1 also constitute advantageous and preferred refinements and combinations of the technology disclosed in DE 44 39 307 A1 and DE 197 21 688 A1, the entire content of which, as well as that of the laid-open publication of EP 98115809.0 are herewith incorporated in full into the present documents in order to avoid mere identical repetition. The individual characteristics and combinations of characteristics can, in particular, be combined with the above-explained stroboscopic technology, although this is not mandatory or exclusive.